Forming tool for reducing stock



y 1954 M. J. KREUTZER 2,682,848

I FORMING TOOL FOR REDUCING STOCK Filed Feb. 12, 1952 4 1 g. 4 INVENTOR.

Michael J. Kreufzer, n/45m r124;

Patented July 6, 1 954 EORMJNG TOOL- FOR REDUCING" STOCK Michael Ji Kreutzer; Dayton, Ohio, assignor. to. General Motors Corporation,, Dayton; Ohio,, a-

corpnratibnjof Delaware Application February 12, I952; Serial No. 271,196

7 Claims. 1:

This invention relates to refrigerating apparatus-and more particularly to a method and a tool for spinning tubular stock for use in fabricating refrigerant-filtersand the like.

It isan object of this invention to provide a spinning device which is" an improvement over spinning devices of the type'shown in- Hill Reissue Patent 22 3465;

More particularly, it is an object of this invention to provide a spinning device and method which eliminates'the needfortheso-called heat ring of the" Hill Reissue Patent No. 22A65-and which utilizes a spinning tool having a simple construction wherein'the' area of contact between the tool and the'tubular stock constitutes considerably less= than56% of the-circumference of the stock.

Another object of this invention is to provide a spinning'device which requires so l-ittle'pressure for-its" operation that itmay'be used in a com vention-al' drill press;

Stillanother object ofthis invention is-toprb 'vide a spinning-device comprising-a holder which removably supports-a tube guide and-a separate spinning insert.

Aiurther object or this-invention is to'provide asimple and inexpensive spinning-tool which is so constructed and-- arranged that sucoessivepon tions of'thesto'ck to be spun are free'ito" distort or-deform during the-spinning operation;

Still another'object of this invention is toproyidea spinning-' toolwh-ieh not only servesto-redueetheouter diameter-of tubular stock-butalso serves to form'an internal'shoulder on-t-he'tubular stock. p 7

Further" obj ects and" advantages of the present invention will be apparent from the following description, referencebeing had to the accompanying drawings wherein a preferred form of the invention is clearly shown.

In the drawings: 7

Figure l is a vertical sectional view showing a preferred embodiment ofthe invention.

Figure 2 isanendelevational view'showing the shape ofthe spinning insert.

Figure 3 is a sectionalview withpartsbroken away and taken substantially on line 3-3 of Figure l.

Figure 4 isa fragmentary elevational view with parts broken away showing a section of tubing which has had its one end reduced by meansof the device shown in Figures 1 through 3 and showing the internal shoulder arrangement for position-inga strainerelmentwithin the tubing. In manufacturingvarious types of small tubu- 2: lar housings; it is standard practice. to place a length of tubular stockin. a. holderand tnexert a reducing pressure 011 thestock by meansoi a spinning tool as the tubular stock and: the tool are relatively rotated and moved towardeach other. The spinning tools used: in the process are usually provided with an. annular.- portion which gradually decreases in cross-section: and thereby-exerts a: reducing pressure continuously around the'entirecircumferenceof the stockto progressively heat the latter to aneasily workable condition. Prior to this invention it. was consideredneeessary to have the spinning device exert a very high pressu-reon the surface being shaped and" to engage the stock throughout. a major portion of the circumference whereas it has been discovered that a spinning tool'havinga plurality of properly designedrelatively narrow axially extending rib portions for engaging the stock canbe usedvery effectively to reduce the diameter oi tubular stock. 'Aswill beexplained morefully hereinafter, the stock engaging ribs, are relatively straigl-it sided so as toengage the stock alonga'straight-line.

Referring now tothe drawing wherein there is shown a preferred embodimentof the invention, referense numeral- I0 generally designates a holdingfixture which-is provided with-a spindle l2 for usein mounting the holding" fixture or adapter in a eonventional' drillla press. The adapter [-0 servesto support a spinning insert M and a pilot element-l 6' as bestshownin: Figure l. The spinning insert I 4 is-provided with a central bore for receiving the stock: to be' sp-un. The reduced end" orthe tubing moves into'the space between thespinning insert and the pilot element l6. The central bore consists'oia first portion I'8 of substantially uniform diameter and a second tapered portion 29 which is somewhat oval in cross-sectionas best shown in Figure 2 of the'draw-ing'.

By virtue of the oval shape of the spinning insert, it is obviousthat it will engage-the-tubing only adjacent'the side-portions 2-2 which project slightly as shown and which constitute rib-like formations for engaging the tubing. As, best: i1- lustrated in FigureLZofi the drawing, the rib portions. 22 are diametrically opposite. one another so as co-engage the: opposite sides of the. tubing along a narrow: region. extending substantially axially. The tubular stoekzis free to expand as it; moves pasteach rib portion- 22, due to the oval. shapeoi the taperedhoreil'i; The repeated expansion and recompressioniof the tubular'stock generates heat which facilitates working the stock.

A guide ring has been provided as shown and serves to guide the stock as it is fed into the spinning insert. This ring does not contact the stock throughout its entire circumference but can only contact the stock along three spaced points as best illustrated in Figure 3 of the drawing as approximately two-thirds of the inner surface of the guide ring has been cut away as indicated at 32. The minimum internal diameter of the guide ring is preferably slightly greater than the outer diameter of the tubular stock so as to prevent binding. The guide ring is made separate from the spinning insert [4 with the result that it is not necessary to replace the guide ring when replacing the spinning insert and vice versa. Furthermore, by making the guide ring as a separate element it simplifies the manufacture of the spinning insert. The adapter Ill is provided with lugs which engage within slots 31 formed in the outer periphery of the guide ring 30 as shown in Figure 3. A retaining cap or ferrule 39 is provided as shown for removably holding the guide ring 30, the spinning insert it and the pilot is in place in the fixture l0.

Figure 4 shows a section of tubing 40 which has had its one end 42 reduced in diameter by means of the device shown in Figures 1 through 3. Spinning devices of the type shown herein may be used to reduce the diameter of tubing for many different uses, but for purposes of illustrating the invention Figure 4 shows a portion of a filter for use in a refrigerating system.

The pilot element 16 serves to engage the inner circumference of the tubing after it has had its diameter reduced by the spinning insert M. It will be noted that the leading end of the pilot element is of a reduced diameter whereby a shoulder 3 is formed on the pilot which in turn serves to form a shoulder 36.(see Figure 4) internally of the tube. This shoulder 36 then serves as a stop or positioning means for use in positioning the strainer element 38 within the reduced portion 12, of the tubing.

The pilot element 16 is provided with hardened inserts M which resist. wear better than the rest of the main body of the pilot. These inserts are preferably made of tungsten carbide. The opposite sides the pilot have been flattened as shown so as to reduce the possibility of binding between .the tubing and the pilot. The flattened sides may also be used as passages for a cooling fluid in those installations in which a cooling fluid is circulated through the tubular stock during the spinning operation.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In a forming tool for reducing the diameter of tubular stock, a spinning element having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the element, the wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and tool, said wall being provided with relief recess means extending longitudinally substantilaly throughout the length of said cavity, the area of the stock engaging wall of the cavity being substantially less than the area of said relief recess whereby only a minor portion of the circumference of the stock is engaged by the element during the reducing operation leaving the remaining portion free to deform into said relief recess in response to the reducing operation, and a pilot element projecting into said cavity for limiting the internal diameter of the deformed stock, said pilot element having a shoulder formed thereon so as to form a shoulder on the internal surface of said stock.

2. In a forming tool for reducing the diameter of tubular stock, a spinning element having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the element, the wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and tool, said wall being provided with relief recess means extending longitudinally substantially throughout the length of said cavity, the area of the stock engaging wall of the cavity being substantially less than the area of said relief recess whereby only a minor portion of the circumference of the stock is engaged by the element during the reducing operation leaving the remaining portion free to deform into said relief recess in response to the reducing operation, a pilot element proiecting into said cavity for limiting the internal diameter of the deformed stock, said pilot element having a shoulder formed thereon so as to form a shoulder on the internal surface of said stock, and an insert of relatively wear-resistant material in the face of said pilot at the place where the pilot first engages the interior of the oncoming stock.

3. In combination, a forming tool for reducing stock having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the tool, the wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and the tool, said wall being provided with a plurality of relief recesses separated by substantially straight sided ribs extending longitudinally substantially throughout the length of said portion of progressively diminishing cross-section, said relief recesses comprising a major portion of the inner circumference thereof, a holder for removably supporting said forming tool, and guide means for said stock removably carried by said holder, said guide means comprising a ring having a plurality of inwardly extending projections for engaging the stock at spaced points about its periphery.

4. In combination, a forming tool for reducing stock having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the tool, the wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and the tool, said wall being provided with a plurality of relief recesses separated by substantially straight sided ribs extending longitudinally substantially throughout the length of said portion of progressively diminishing cross-section, said relief recesses comprising a major portion of the inner circumference thereof, a holder for removably supporting said forming tool, guide means for said stock removably carried by said holder, said guide means comprising a ring having a plurality of inwardly extending projections for engaging the stock at spaced points about its periphery, and a pilot element removably carried by said holder for engaging the inner periphery of said stock.

5. In combination, a forming tool for reducing stock having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the tool, the wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and the tool, said wall being provided with a plurality of relief recesses separated by substantially straight sided ribs extending longitudinally substantiallyvthroughout the length of said portion of progressively diminishing cross-section, said relief recesses comprising a major portion of the inner circumference thereof, a holder for removably supporting said forming tool, guide means for said stock removably carried by said holder, said guide means comprising a ring having a plurality of inwardly extending projections for engaging the stock at spaced points about its periphery, and a pilot element removably carried by said holder for engaging the inner periphery of said stock, said pilot element having portions of its periphery spaced from the inner Wall of the stock so as to prevent seizure between the pilot and the stock.

6. In combination, a forming tool for reducing stock having an axially extending cavity at least a portion of which is of progressively diminishing cross-section longitudinally of the tool, the Wall of said cavity being adapted to engage and reduce the stock upon relative rotation and axial movement toward one another of the stock and the tool, said wall being provided with a plurality of relief recesses separated by substantially straight sided ribs extending longitudinally substantially throughout the length of said portion of progressively diminishing cross-section, said relief recesses comprising a major portion of the inner circumference thereof, a holder for removably upporting said forming tool, guide means for said stock removably carried by said holder, said guide means comprising a ring having a plurality of inwardly extending projections for engaging the stock at spaced points about its periphery, and a pilot element removably carried by said holder for engaging the inner periphery of said stock, said guide means having a portion in engagement with a portion of said pilot so as to hold said pilot in position Within said holder.

7. In combination, a forming tool having a cavity for receiving and reducing the diameter of tubular stock, guide means separate from said forming tool for directing the incoming stock into said cavity, and a holder having a socket for receiving said forming tool and said guide means, said holder including a removable clamping means for removably clamping said guide means and said forming tool in place within said holder, said guide means comprising a ring having means for engaging said tubular stock throughout less than 360 of its circumference.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 172,443 Ide Jan. 18, 1876 1,879,078 Carlsen Sept. 27, 1932 2,325,522 Laver et al July 27, 1943 2,349,168 Hill May 16, 1944 2,358,711 Hill Sept. 19, 1944 2,449,247 Paucek Sept. 14, 1948 

